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In an age when Apple has become the top music retailer without selling a single physical disc, audio engineers are increasingly creating specially mastered versions of songs and albums designed to counteract the audio degradation caused by compression. Though audiophiles typically scoff at paying for compressed audio, preferring vinyl or high-end digital formats such as DVD-A, mastering engineers are doing their best to create digital masters that can pass through Apple's iTunes algorithms with minimal sonic corruption.

To highlight work done to improve the sound of compressed music files, Apple recently launched a "Mastered for iTunes" section on the iTunes Store. It now also provides a set of recommendations for engineers to follow when preparing master files for submission to the iTunes Store. To qualify for the "Mastered for iTunes" label, Apple says that files should be submitted in the highest resolution format possible, and remastered content should sound significantly better than the original.

How does this work? Ars spoke with Masterdisk Chief Engineer Andy VanDette, who recently completed a project remastering the bulk of Rush's back catalogue. As part of the process, VanDette created special versions of each song specifically for uploading to the iTunes Store. He described the often lengthy, trial-and-error process of trying to make iTunes tracks sound as close as possible to polished CD remasters.

The state of compressed audio

All music purchased from iTunes is compressed using a "lossy" compression algorithm called Advanced Audio Coding (AAC). Lossy compression algorithms toss out some of the information contained in a digital file in exchange for very small file sizes. Formats like AAC (and MP3) try to be intelligent about what information is tossed out in order to maintain fidelity with the original, uncompressed file. They do so by eliminating frequencies and harmonics least likely to be discerned by the average listener.

(The JPEG image format attempts to do the same thing with photos, eliminating details and colors that aren't likely to be noticed by the average viewer. This is why JPEGs can sometimes look blocky if saved at a high compression rate.)

A number of music industry luminaries, including Jimmy Iovine (head of Interscope-Geffen-A&M), Dr. Dre, and most recently Neil Young, have bemoaned the fact most music now plays back from a compressed file, resulting in a "degradation" of the sound an artist originally tried to create.

"We live in the digital age, and unfortunately it's degrading our music, not improving it," Young said in January during the D: Dive Into Media conference.

Young and his cohorts are attempting to make uncompressed, higher-end audio formats a common standard across the industry. Music throughout the last decade is typically recorded using 24-bit samples at 96kHz, and advances in computing power and hard disk space have recently made even higher quality, 24-bit 192kHz digital recording possible.

However, even the standard CD format comes in a much lower resolution—just 16-bit 44.1kHz. Compared to 24-bit 192kHz digital audio, a finished CD only has roughly 15 percent of the information captured during the recording process. Compressing the songs on a CD further into 256kbps AAC "iTunes Plus" format cuts the data down to just one-fifth of the size of CD audio, or as little as three percent of the original 192kHz recordings.

"We're working with [Apple] and other digital services—download services—to change to 24-bit," Iovine said. Young also admitted to working with Apple to make 24-bit audio standard across its mobile devices, though he suggested that no progress has happened since Steve Jobs—known for his love of classic rock—died last October.

As an audio engineer, VanDette is "hopeful" hardware and storage capabilities will one day make uncompressed, 24-bit audio a practical standard. For instance, digital music service HDtracks already offers a catalogue of 24-bit audio files at various sampling rates up to 192kHz. But such audiophile quality is only beneficial to those with expensive stereo equipment capable of reproducing the subtle nuances captured in these higher-quality files.

"I am encouraged to see a growing catalog at HDtracks, but being able to have your entire album collection in your pocket is cool, too," VanDette told Ars. As long as iPhones and iPods are the most common playback equipment, and the iTunes Store the top source for music, compressed audio files are, practically speaking, here to stay for the foreseeable future.

If you can't beat 'em, join 'em

Want an uphill battle? Try pushing the bulk of consumers to embrace niche audiophile formats and upgrade to capable equipment. Instead, audio engineers have taken to mastering versions of songs and albums specifically for the iTunes Store.

A similar mastering process is already done to prepare albums for other physical formats. As previously noted, recording is typically done in a digital 24-bit 96kHz format. However, audio released in CD format is 16-bit 44.1kHz quality, requiring a conversion from the original source. Engineers adjust equalization, levels, compression, noise filters, and other parameters to cram as much of the source material into those limits.

(Returning to our earlier photo analogy, the process is similar to converting a 14-bit RAW file from a DSLR into a standard 8-bit TIFF.)

Recording can also be done at varying bit-depths and sampling rates. Sometimes it's still done using vintage analog gear (see recent Grammy winners, The Foo Fighters). Albums are still released on analog vinyl format, and in some cases are made available in high-end digital formats such as Super Audio CD (SACD) or DVD-Audio (DVD-A). A mastering engineer will take whatever source material is provided—analog or digital—and optimize it for each release format, taking into account each format's unique strengths and limits.

VanDette explained how mastering varies depending on the age of the original recordings as well as the final output format. Many master recordings for Rush albums are from vinyl's heyday, he said. "Back then we would try and hide as much top end as possible, knowing that the end users' styli would be crap."

"Most listeners today swear they love the bottom end on vinyl, but I remember in the heyday of vinyl, it was all about top end," VanDette told Ars. "'If we could only have a clear top end without all those pops and clicks' we thought," he said, noting the tendency of low-end record players to introduce unwanted noise. "Back then, bottom was the enemy. It made the grooves [in the vinyl] too wide, and forced us to turn down the overall level of the disc."

The constraints of vinyl aren't a concern when mastering for a CD, so it's possible to boost overall levels as well as low frequencies without ruining the rest of the mix. "While remastering the classic Rush albums, I added as much LF as I could, always aware not to cloud the classic 'ping' on Neil's snare, muddle Geddy's voice, or bury Alex's guitar," he said.

"These are some finely balanced mixes, even 35 years later," VanDette said. "I wanted to make sure the listener still heard the classic album come through, without it being too loud, boomy, or modern sounding."

344 Reader Comments

Nyquist only covers one easily-digestible aspect of what a given sample rate accomplishes. Take a look at the number of samples taken to define one digital word. More samples is a more clearly defined facsimile of the natural waveform.

You remember the stairstep graphs, right? The ones with lots of tiny stair steps more closely approximating a curve? That's more samples taken, and is unrelated to frequency response.

You should probably find an oscilloscope and connect it to whatever digital sound interface is handy. Start playing a 100Hz tone, stabilize the display (if the osc. is analog) and then zoom in the time axis.

Nyquist only covers one easily-digestible aspect of what a given sample rate accomplishes. Take a look at the number of samples taken to define one digital word. More samples is a more clearly defined facsimile of the natural waveform.

You remember the stairstep graphs, right? The ones with lots of tiny stair steps more closely approximating a curve? That's more samples taken, and is unrelated to frequency response.

The output of a properly functioning reconstruction filter does not exhibit a bunch of tiny stair steps. Everything that's "steppy" about those stair steps is artifacting at and above the Nyquist frequency. Remove all the steps, and the remaining waveform is a perfect reconstruction of the (band-limited) original waveform. That's what the Nyquist theorem is telling you.

And that 8bit TIFF is exactly the same as that 14bit RAW for those colors that fall within the same color space. How is the comparison "utterly, absolutely wrong magical voodoo thinking"?

Eyes do not work the same way ears do, and don't have the same limitations. This is again an apples to oranges comparison. The equivalent of frequencies outside the hearing range for images would be the infra-red and ultra-violet wavelengths.

It's probably more fair to say that it's harder to describe sound than it is vision, and even harder to objectively test for sound differences. This is particularly the case since vision is only perceived through eyes, whereas sounds can be in ways other than through ears. Examples would include low frequencies too low to be heard (but felt) and on the other end, what a dentist's visit can produce when the sonic cleaning pick resonates on a tooth and [only] you "hear" a high-pitched squeal that was never directly made.

1) Some artists out there want to promote listeners to get 24-bit, 96kHz audio. As has been shown in the comments, most people probably won't notice the difference.

2) Some audio engineers are ensuring that their mixes still sound good after they apply AAC compression. The downsampling from 24/96 to 16/44 is a given. That happens no matter what - CD or MP3 or AAC, you go down to 16/44.

Unfortunately there wasn't a lot of discussion about actual mixing and mastering techniques - things like applying frequency boosts and cuts, compression, and similar. One of the posters said that there is a difference between file compression (where you make file sizes smaller) and audio compression (where you squash dynamic range in an effort to make things sound louder). This article seems to suggest that audio guys are now considering file compression when they're applying their mixing and mastering tools (tools like the compressor and EQ). The audio engineer's job, of course, is to make sure that the mix not only sounds "good" (vocals are balanced with backgrounds; low noise; arguably, things are loud because humans perceive loud as "better") but also that it sounds good on many types of systems and on many types of file formats.

Nyquist only covers one easily-digestible aspect of what a given sample rate accomplishes. Take a look at the number of samples taken to define one digital word. More samples is a more clearly defined facsimile of the natural waveform.

You remember the stairstep graphs, right? The ones with lots of tiny stair steps more closely approximating a curve? That's more samples taken, and is unrelated to frequency response.

You should probably find an oscilloscope and connect it to whatever digital sound interface is handy. Start playing a 100Hz tone, stabilize the display (if the osc. is analog) and then zoom in the time axis.

You'd be surprised.

You may surprised to know I don't listen to test tones, and that perhaps---just perhaps--- measurements of simple test tones isn't perfectly suited to measure what's being experienced as complex music by the listener. Listening is the one thing no test equipment can actually do. Equipment measures, and only what you tell it to measure, based on what you know "should be true." If that's scientific, great. But irrelevant, sorry.

Are we OK on that, or do I (for some reason) need to accept what "should" be true, as true, in order to know what I hear?

I'm with several other posters here in that this article has a lot of mistruths and lies. Tweaking the master for AAC at 256 kbps is just nonsense. It will be plenty transparent. This Mastered for iTunes branding is nothing more than another opportunity to sell you the same tracks, albeit with likely worse quality.

The Rush albums are one of the most egregious examples of poor mastering and squashed dynamics. Quite ironic that this mastering engineer was interviewed for this article!

Red Book CD, when properly mastered, can transparently play back all audio frequencies that humans can hear.

Nyquist only covers one easily-digestible aspect of what a given sample rate accomplishes. Take a look at the number of samples taken to define one digital word. More samples is a more clearly defined facsimile of the natural waveform.

You remember the stairstep graphs, right? The ones with lots of tiny stair steps more closely approximating a curve? That's more samples taken, and is unrelated to frequency response.

The output of a properly functioning reconstruction filter does not exhibit a bunch of tiny stair steps. Everything that's "steppy" about those stair steps is artifacting at and above the Nyquist frequency. Remove all the steps, and the remaining waveform is a perfect reconstruction of the (band-limited) original waveform. That's what the Nyquist theorem is telling you.

It's helpful to include the part where Nyquist assumed a very high sample rate (infinite sampling, actually) was occurring.

I'm with several other posters here in that this article has a lot of mistruths and lies. Tweaking the master for AAC at 256 kbps is just nonsense.

Nonsense, why exactly?

Quote:

This Mastered for iTunes branding is nothing more than another opportunity to sell you the same tracks, albeit with likely worse quality.

Nobody is trying to "resell" anything. This is an attempt to make compressed audio sound better, full stop. IF an audio engineer thinks it sounds better, I trust his word. Masterdisk is a trusted mastering studio, and VanDette's reputation is sound.

Quote:

The Rush albums are one of the most egregious examples of poor mastering and squashed dynamics. Quite ironic that this mastering engineer was interviewed for this article!

VanDette's remasters haven't been released yet, so it seems pretty unfair to make any sort of conclusion as to how they sound. The 1997 remasters are what's currently available, so maybe that is what you are complaining about.

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Red Book CD, when properly mastered, can transparently play back all audio frequencies that humans can hear.

No disagreement here. Where did the article state that was any different? It's Neil Young et al that make those suggestions, not me—or even VanDette, for that matter.

Sure enough another thread full of people arguing over the finer points of audio quality, which is exactly what the labels want you to argue over. Look! ***Shiny Object***

People are missing the bigger point: the labels repackage the same tracks over and over again, sometimes in compilations, sometimes in an updated album with Bonus. Tracks., and sometimes r e m a s t e r e d ! ! And they get to charge you all over again, double- or triple- or quadruple-dipping for the same music every time.

Remastering is fine and all, but when the labels give us an upgrade credit for all the music that we've already paid for instead of reseting the cash register to zero then people will maybe stop considering them to be money-grabbing bastards.

2) Some audio engineers are ensuring that their mixes still sound good after they apply AAC compression. The downsampling from 24/96 to 16/44 is a given. That happens no matter what - CD or MP3 or AAC, you go down to 16/44.

Actually, VanDette doesn't digitally downsample. His method is to play back the original masters through a high-end analog setup, and re-digitize as necessary for each format. So, if he's creating a DVD-A master, he'll sample at 24/96, or for CD he'll sample at 16/44.1. He did say sometimes for CD he'll sample at 88.2 and downsample to 44.1 depending on noise levels, but I'm pretty sure that exactly halving the sample rate avoids the noise typically introduce by DSP.

People are missing the bigger point: the labels repackage the same tracks over and over again, sometimes in compilations, sometimes in an updated album with Bonus. Tracks., and sometimes r e m a s t e r e d ! ! And they get to charge you all over again, double- or triple- or quadruple-dipping for the same music every time.

Sure enough another thread full of people arguing over the finer points of audio quality, which is exactly what the labels want you to argue over. Look! ***Shiny Object***

People are missing the bigger point: the labels repackage the same tracks over and over again, sometimes in compilations, sometimes in an updated album with Bonus. Tracks., and sometimes r e m a s t e r e d ! ! And they get to charge you all over again, double- or triple- or quadruple-dipping for the same music every time.

Remastering is fine and all, but when the labels give us an upgrade credit for all the music that we've already paid for instead of reseting the cash register to zero then people will maybe stop considering them to be money-grabbing bastards.

Anyway, back to the discussion about psychoacoustic nuances....

Even if people consider them to be money-grubbing bastards, the fact is that until people just stop buying the new shiny remasters, they won't consider upgrade credits or anything else. Even outside of audio the same thing exists. How many times has Star Wars been "remastered"? Classic Disney movies?

Voting with your wallet only works when you're not the only one doing it, unfortunately.

Everything that's "steppy" about those stair steps is artifacting at and above the Nyquist frequency. Remove all the steps, and the remaining waveform is a perfect reconstruction of the (band-limited) original waveform. That's what the Nyquist theorem is telling you.

It's helpful to include the part where Nyquist assumed a very high sample rate (infinite sampling, actually) was occurring.

Why would there need to be a sampling theorem for infinite sampling rate?

As a live audio engineer, I can tell you this: No one will ever agree on what sounds good. Seriously. It's too loud to person X. It's too quiet to person Y. Person Z can't hear the violin over the drum kit. Person $ thinks it's too boomy. And the director says there's too much reverb on the bass guitar, and I'm adding none, and it was his idea to do Hair in a theatre, with no curtains on the walls. It gets even more fun when people will say it sounds better when I turn some random, unconnected knob on the board to "adjust" the low end or whatever is bothering them, and I'm not actually adjusting anything. My standard of knowing I'm mixing a musical just right is when I get 1/2 complaints, and 1/2 compliments.

I had someone criticize me once for doing my sound effects for a live musical off of minidisc because the ATRAC3 compression algorithms are "bad". When I asked him what he thought I should be using, he replied with "DAT of course!" (this was back around 2000). I laughed.

The problems only compound in the recording world where you have over a million different combinations of output transducers and equipment with various de/compression algorithms and bit rates. Someone might've used MP3 algorithm brand T to encode the file, and playing back on a player with brand S codec, and there are very slight, minute differences. Each engineer and producer has their own ideas of what it should sound like. Arguing over bit rates and compression algorithms is pretty silly. While there are always "purists" out there who will pay $50+ for some silly custom copper RCA cable because they think they can hear a difference, the reality is that they're a very small minority.

My standard of audio is simple. I use studio standard Sony MDR-7506 cans ($119) on a player , or their home audio equivalent (Sony MDR-V6, which is the same drivers, with a nickel plug instead of gold, and a lower warrantee, and they're usually around $79), and I play the audio file. These cans are pretty much an accepted global studio standard. No need for stupidly over-priced "Dr Dre Beats" or the silly junk Bose tries to sell you. Beyond that, if I don't like what I'm hearing out of my less expensive ear buds, it's because they suck, not the track.

As an audio engineer, VanDette is "hopeful" hardware and storage capabilities will one day make uncompressed, 24-bit audio a practical standard. For instance, digital music service HDtracks already offers a catalogue of 24-bit audio files at various sampling rates up to 192kHz. But such audiophile quality is only beneficial to those with expensive stereo equipment capable of reproducing the subtle nuances captured in these higher-quality files.

If I pay the full price for a audio download then I expect the complete, uncompressed, uncut, uncorrupted version regardless of whether I can tell the difference or not. Imagine you went to a restaurant and ordered a bottle of Moet Chandon and when it arrived it was little more than Lindauer bubbly. Would you accept the excuse, "well, most people can't really tell the difference between the two" - of course not, you'd be sitting there saying, "but hang on, I asked for Moet Chandon and I expect Moet Chandon regardless of whether or not 90% of people can't tell the difference.

Btw, thank you for the link to HDtracks - hopefully more artists will be added. It is pathetic that in a day of electronic downloads we don't see record companies put online all their back catalogue of out of bring music so that people can buy and download it. I want to buy 'Home Brew' and 'It's private tonight' by Arthur Adams which are vinyl and out of print yet there is no place other than bootleg vinyl rips where I can buy it from. I've got cash, I'm willing to hand over that cash but the record companies are too bloody lazy to provide it.

If I pay the full price for a audio download then I expect the complete, uncompressed, uncut, uncorrupted version regardless of whether I can tell the difference or not.

Unless you're buying the audio masters, then there's no reason you should expect this. It isn't what you got when you bought vinyl, tapes, or CD's - did you expect that then, also? (More importantly, I don't think anyone ever told you that that's what they were selling you.)

My standard of knowing I'm mixing a musical just right is when I get 1/2 complaints, and 1/2 compliments.

That's funny - I can absolutely picture this happening. Too much of our perception of music is entirely in our heads. I'll bet there were situations where you could've just told someone that you changed something without actually doing it, and they would've reported that you'd fixed it.

Thanks for the post. It's always nice to get the opinion of someone in the trenches.

That study showed that with experience to crap, people will learn to prefer crap because it's all they know. That's not the same as saying they implicitly, and without any other influences, would continue to do so.

You can carry this to its logical extension and see how the students would eventually never want to hear live musicians perform because it wouldn't sound "as good" as their iPods. If that makes sense to anyone, than so does the notion that preferring a lower-quality recording is the worthy goal, instead of one that more faithfully recreates the original performance.

The question remains as it always has: strive for better, or be happy with junk and pull everyone else down as well, who might not appreciate that?

Question is, what defines good?

Would it be the raw output of the instruments simply run thru a high (that is a question on its own, what bit rate is "high enough" to be "good"?) bitrate ADC and then stored in some lossless way?

Thing is that all audio recorded for commercial sale have been mixed in some way.

The only criteria i guess is that whatever reaches the ears of the listener has the waveshape the artist wanted it to have. This because even the ears of the eventual listener affect the listeners experience of those waves.

Btw, was there not a claim that the internal equalizer of the original iPod was specifically tuned to Jobs' ears?

Everything that's "steppy" about those stair steps is artifacting at and above the Nyquist frequency. Remove all the steps, and the remaining waveform is a perfect reconstruction of the (band-limited) original waveform. That's what the Nyquist theorem is telling you.

It's helpful to include the part where Nyquist assumed a very high sample rate (infinite sampling, actually) was occurring.

Why would there need to be a sampling theorem for infinite sampling rate?

How else would you know not to use frequencies > infinity/2 ?

But that ignores that it wasn't infinite sampling rate, but infinite sampling time. ;-)

If I pay the full price for a audio download then I expect the complete, uncompressed, uncut, uncorrupted version regardless of whether I can tell the difference or not.

Unless you're buying the audio masters, then there's no reason you should expect this. It isn't what you got when you bought vinyl, tapes, or CD's - did you expect that then, also? (More importantly, I don't think anyone ever told you that that's what they were selling you.)

But if they were selling AAC albums at 1/2 the price of the CD then I'd be more than happy to pay for it but the reality that isn't the case. I am being charged for an inferior product, regardless of whether I can tell the difference, at the same price as a CD which is at a higher quality when compared to the downloaded version.

As noted, if all the record companies got together and offered FLAC downloads of all their music (both present and past catalogue) I'd be more than happy to buy all the bootleg vinyl rips I have on my external hard disk - but I'm not going to do that until the record companies meet me half way.

I'm with several other posters here in that this article has a lot of mistruths and lies. Tweaking the master for AAC at 256 kbps is just nonsense.

Nonsense, why exactly?

Quote:

This Mastered for iTunes branding is nothing more than another opportunity to sell you the same tracks, albeit with likely worse quality.

Nobody is trying to "resell" anything. This is an attempt to make compressed audio sound better, full stop. IF an audio engineer thinks it sounds better, I trust his word. Masterdisk is a trusted mastering studio, and VanDette's reputation is sound.

Nonsense? Because there are no blind A/B tests that show that humans can tell any difference. Somewhere, since needs to come into play.

You take the audio engineer's word for it? What about other audio engineers who would explain to you why it doesn't matter and why without an A/B test its pointless?

For anyone here who is arguing otherwise, you just need to do a little more research. If you care to take the time to educate yourself on some of this stuff, this long thread could be a good resource:viewtopic.php?f=6&t=1164451&hilit=truepusk

Dumb ploy by apple, dumb article, but as others pointed out, they are common misconceptions, and consumers are dumb.

I am very thankful that there is a well informed and vocal ars community that voices their opinions loud enough in the comment section to hopefully have an impact on readers that might otherwise be misinformed.

The video doesn't get audio compression, but IIRC, it does speak to the importance of A/B blind listening tests and that anything not supported by that should be discarded. Thus, as others have said, show the A/B test, otherwise it's just silliness.

Ugh - ABX > what some guy at Masterdisk thinks (btw don't ever use Masterdisk - their service is EXTREMELY hit or miss)

As a professional recording engineer, I use higher bit rates in an attempt to alleviate loss during digital and analog processing - some of my effects are not 100% digital, so often I have to send some channels or ALL channel back out through an analog processor to get the sound we're looking for (generally speaking tube compressors "emulation" is not a solved problem). This is really it, bitrot during the recording & mastering processes and it's very edge case stuff - if I use the same devices I use now to record at 24bit@192kHz and instead do it at 16bit@44.1kHz, I have a VERY difficult ever telling the difference - much of the improvement is is in the speed of the computer (not because of just MOAR POWER, but because everything could be moved into software and off stupid limiting hardware) and the improvement in ADCs.

Still waiting for some blind tests where anyone, anywhere can tell the difference between uncompressed and 256 kbit MP3/AAC. Been waiting 10+ years.

it's actually pretty easy with some moderately priced equipment. you will not be able to discern the difference if you're using apple earbuds and the ipod DAC/AMP.

I have a battery operated Fiio e7 DAC ($85) to play music from my Nano. I use a LOD connector, so I bypass the iPod's DAC and AMP. The Fiio does all the work sends sound to my Westone 3's ($300).

For the desktop I have a nuForce icon ($129) and Senn 380 HD pro - closed (~$220), Beyerdynamic 880s 32 ohm- semi closed. (~$300) and a pair of Grado 325s open (~$300). All are circumaural.

128 bit just sucks. period. can't listen to those recordings now. the sound is so flat it's like listening through a loaf of bread.

256 is ok but the sound is still a bit murky. I'm sure with higher end equipment 256 will sound like junk too.

hear the difference if you use ALAC or FLAC.

try it yourself. get a pair of decent cans (grado sr60's are a great place to start -$70.) try them first with just the ipod, then try it with a DAC (you can return all of it to amazon if you still don't hear a difference). I bought 6 or 8 pairs of cans before I picked the ones I have.

I used to be like you.. thought I'd never be able to hear the difference and thought audiophiles were full of shit... so either I was wrong and you can hear a difference, or I'm now full of shit too

if you take the DAC out of the mix, it's going to be harder to discern the difference.. and forget about it if you're using those craptastic apple earbuds (i never used those) 128 and direct from CD will sound the same.

[I have a battery operated Fiio e7 DAC ($85) to play music from my Nano. I use a LOD connector, so I bypass the iPod's DAC and AMP.

Unfortunately, that's incorrect. The E7 cannot utilize any digital outputs that the iPod line might have (and the last I checked, that's absolutely none), so you're actually just feeding the line-level output of your Nano into the E7's amp section. The last iPods with good DACs in them were the 5.5g Classic, which had a great Wolfson chip. If you want to use the E7's DAC, plug it into your computer via USB. If you want a good amp for your portable player... you shouldn't have bought the E7. There are better choices.

Being aware of that, I bought the Fiio E10 for my PC. Better DAC and amp, no wasted components.

Your ability to discern 256+ is most likely false. Run a true ABX with something like this. You'll surprise yourself.

As far as I can tell, some of you are are trying to say that AAC compression does not in any way affect te sound quality, while others are arguing compressed music is awful? Which is it?

If we accept the fact that a lossy compression algorithm makes the audio sound worse, then isn't it worthwhile to try and tweak the audio to sound better when compressed? I mean, we don't have infinite bandwidth and storage yet, so compressed audio is simply a given at this point. So why not try to make it sound (if even subjectively) better?

If you assume no one can tell the difference, then making the effort can't actually hurt anything, right?

I'm certainly not trying to say iTunes should go losslesly compressed 24/96 audio anytime soon (if ever), and I've written an article linked in the OP) explaining why I think that's a waste. But frankly I see no harm in mastering for iTunes Plus format, given that's it's a known (if poorly understood) target, much as vinyl, cassette, and CD were before it.

As far as I can tell, some of you are are trying to say that AAC compression does not in any way affect te sound quality, while others are arguing compressed music is awful? Which is it?

If we accept the fact that a lossy compression algorithm makes the audio sound worse, then isn't it worthwhile to try and tweak the audio to sound better when compressed?

What we - the sane ones, at least - are saying is that properly-written lossy compressors like LAME produce files that are indistinguishable from a lossy source, like FLAC, ALAC, or CD, to the vast majority of listeners. This has never been disproven. I can't speak for AAC - done right, it shouldn't have flaws, but Apple's implementation may be imperfect, making it produce inconsistent results.

The engineer's complaint was that using Apple's AAC encoder is "like polishing your Bentley in total darkness, then turning on the lights to see where you missed." Quirky, as it's describes in the article. If you can't predict it, you can't master for it. That doesn't seem to be what they're doing, either. They're changing the sound characteristics to suit their preferences, modern preferences (BASS IT UP BRO - "I added as much LF as I could"), and to make it louder.

What's going to come out of this "Mastered for iTunes" gimmick is not going to be lossy music that magically sounds better - it's going to be a mostly-worthless (most likely, but I won't pass judgement until I hear some results) remaster with an "exclusive" label slapped on it, encoded in AAC and sold for $1.29+/track.

Your ability to discern 256+ is most likely false. Run a true ABX with something like this. You'll surprise yourself.

Likely, but it is plausible that the poster can tell the difference. I have done testing to confirm that I can tell a difference between some 256 kbps mp3 (ripped by iTunes) and the original CDs. 320 kbps mp3 and 256 AAC were effectively transparent to my ears with the same samples.

Curiously enough, I have purchased a few 256 kbps AAC tracks from iTunes Store which sounded different from any CD or AAC rip that I have in my possession, but maybe that's an example of super special AAC-specific mastering. I'd be surprised that they actually went through at amount of effort, though. Maybe they just sold me padded 192 kbps tracks.

Likely, but it is plausible that the poster can tell the difference. I have done testing to confirm that I can tell a difference between some 256 kbps mp3 (ripped by iTunes) and the original CDs.

iTunes has a particularly sorry MP3 encoder. Try using a better ripper, like EAC or XLD (Mac), and LAME as the encoder. Use V0, and I guarantee you'll not hear the difference.

Yes, I have also experimented with LAME, but that's a bit irrelevant to what I was saying. My purpose was to check whether the encoder I used regularly (iTunes) was transparent at 256 kbps. It was not. It was easier for me to use the AAC encoder instead or to up the mp3 bitrate to 320 kbps to produce a compressed file that I was satisfied with.

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Also, "hearing" the difference, unless you run a true double-blind test, is quite often placebo. Rip to FLAC or ALAC, ABX, see if you can truly tell.

I performed all the necessary testing. However, I don't see why FLAC or ALAC are relevant to my test of the iTunes mp3 encoder. I said it was plausible to hear a difference between a 256 kbps mp3 and the original CD track; I did not claim that every format exhibits detectible differences.

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Kalessin wrote:

Maybe they just sold me padded 192 kbps tracks.

Easy to tell if you can read spectrum views.

I am familiar with spectral analysis. In fact, much of my professional research work involves signal processing for very high resolution acoustic data, so I don't screw around with this stuff. However, I am unfamiliar with the spectral signature of perceptual encoding at 192 kbps vs. 256 kpbs. If you could point me to some references on this, I would be interested in taking a look. (The original comment was a joke, though).

Ideally, if you already own the track in one format, you should be able to "upgrade" to the (arguably?) better format for free. Odds are that won't happen.

Like the way they took trades for your old Beta/VHS tapes when the LD versions were released, and then they allowed you to trade in your LDs for DVDs (not necessarily an upgrade) and now they're giving you store credit for your DVDs when you purchase the Blu-Ray?

Ideally, if you already own the track in one format, you should be able to "upgrade" to the (arguably?) better format for free. Odds are that won't happen.

Like the way they took trades for your old Beta/VHS tapes when the LD versions were released, and then they allowed you to trade in your LDs for DVDs (not necessarily an upgrade) and now they're giving you store credit for your DVDs when you purchase the Blu-Ray?

By my definition of 'Ideally', yes. The fact that it has never happened led me to add "Odds are that won't happen."

That also ignores the reality that beta/vhs/ld/dvd/br are all completely different hardware, while this is simply audio remastered for the already existing format. Would I balk at buying a Blu-Ray, and then six months later buying a "Mastered for Blu-Ray" version of the same film? Absolutely.